1. Field of the Invention
The present invention relates to an atmospheric pressure detecting device for engine control capable of detecting an atmospheric pressure without using an atmospheric pressure sensor.
2. Discussion of Background
Heretofore, operational characteristic quantities for an engine were electronically controlled on the basis of parameters such as an engine revolution speed, a pressure in the intake manifold, a degree of opening of a throttle valve, an atmospheric pressure and so on. A pressure in the intake manifold contiguous to the intake air passage which is at the downstream side of a throttle valve which is operated in association with an accelerator pedal to limit a quantity of intake air to the engine is detected as a value of the absolute pressure by a pressure sensor. An atmospheric pressure is detected by an atmospheric pressure sensor provided separate from the pressure sensor.
Thus, the conventional atmospheric pressure detecting device has a disadvantage of high manufacturing cost because the atmospheric pressure sensor is required in addition to the pressure sensor.